On self-propelled cotton harvesters, air is used to convey cotton from the picking units to the basket. Once the cotton enters the basket, the air is separated from the cotton so the cotton stays in the basket as the air exits the basket. On current picker designs, the cotton entry area to the basket includes separation structure such as finger grates to allow the air and fine trash to pass through while retaining the cotton. Side screens on the basket also allow excess air to pass out of the basket.
Previously available designs work well for large baskets which have a large surface area and relatively low cotton velocity rates across the grates and screens. However, if the basket or other receiving area has a smaller effective area there is less surface area to discharge the air, and relative air flow is increased. For example, the harvester shown in commonly assigned U.S. Pat. No. 6,263,650 COTTON HARVESTER WITH ACCUMULATOR includes a receptacle which has an effective area only a fraction of that of a conventional harvester wherein an air system directly feeds a large basket. With the smaller effective area, the air velocity increases through the grates and screens. Cotton often is forced through the openings which results in lost crop and blocked screens and grates which have to be cleaned periodically. In addition, the excess air will increase the pressure in a small volume basket or accumulator and reduce the air system performance. The excess air also causes adverse flow patterns which recirculate and blow cotton away from the intended destination.
In a harvester accumulator, the upper portion of the receiving area may require sloping wall structure diverging in a downward direction to feed the relatively small opening while providing sufficient hood separation area. Propelled cotton and debris can easily build up on the sloping wall structure and result in cotton dams and blockages that have to cleared.